I need to replace a particular number of characters, for example 3 characters from the 4th position in a string.
How can I do this?
Perhaps you're looking for the STUFF function:
http://msdn.microsoft.com/en-us/library/ms188043.aspx
Related
I'm building a word unscrambler using MySQL, Think about it like the SCRABBLE game, there is a string which is the letter tiles and the query should return all words that can be constructed from these letters, I was able to achieve that using this query:
SELECT * FROM words
WHERE word REGEXP '^[hello]{2,}$'
AND NOT word REGEXP 'h(.*?h){1}|e(.*?e){1}|l(.*?l){2}|l(.*?l){2}|o(.*?o){1}'
The first part of the query makes sure that the output words are constructed from the letter tiles, the second part takes care of the words occurrences, so the above query will return words like: hello, hell, hole, etc..
My issue is when there is a blank tile (a wildcard), so for example if the string was: "he?lo", the "?" Can be replaced with any letter, so for example it will output: helio, helot.
Can someone suggest any modification on the query that will make it support the wildcards and also takes care of the occurrence. (The blank tiles could be up to 2)
I've got something that comes close. With a single blank tile, use:
SELECT * FROM words
WHERE word REGEXP '^[acre]*.[acre]*$'
AND word not REGEXP 'a(.*?a){1}|r(.*?r){1}|c(.*?c){1}|e(.*?e){1}'
with 2 blank tiles use:
SELECT * FROM words
WHERE word REGEXP '^[acre]*.[acre]*.[acre]*$'
AND word NOT REGEXP 'a(.*?a){1}|r(.*?r){1}|c(.*?c){1}|e(.*?e){1}'
The . in the first regexp allows a character that isn't one of the tiles with a letter on it.
The only problem with this is that the second regexp prevents duplicates of the lettered tiles, but a blank should be allowed to duplicate one of the letters. I'm not sure how to fix this. You could add 1 to the counts in {}, but then it would allow you to duplicate multiple letters even though you only have one blank tile.
A possible starting point:
Sort the letters in the words; sort the letters in the tiles (eg, "ehllo", "acer", "aerr").
That will avoid some of the ORing, but still has other complexities.
If this is really Scrabble, what about the need to attach to an existing letter or letters? And do you primarily want to find a way to use all 7 letters?
I want to create a pattern for an HTML input field that needs to have at least 10 numbers in it and may also have spaces and a plus sign on top of that, but it's not required.
It's important that numbers and spaces can be mixed though. Also, the whole field can only have 17 characters all in all.
I'm not sure if it's even possible. I started doing something like that:
pattern="[0-9+\s]{10,17}*"
But like this, it's not guaranteed that there are at least 10 numbers.
Thanks in advance! Hope the question doesn't exist already, I looked but couldn't find it.
You can use
pattern="(?:[+\s]*\d){10,17}[+\s]*"
The regex matches
(?:[+\s]*\d){10,17} - ten to seveteen occurrences of zero or more + or whitespaces and then a digit
[+\s]* - zero or more + or whitespaces.
Note the pattern is anchored by default (it is wrapped with ^(?: and )$), so nothing else is allowed.
My form field is for users to enter their first name, I want users to be allowed to put a space "billy bob", but MUST require a letter.
My code:
pattern="[a-zA-Z\s]+"
This accepts, letters and spaces. How can I modify it to require the use of at least 1 letter. I want to avoid users entering a name that is all spaces.
Thanks!
Something like this should do it:
([a-zA-Z]+\s*)+
We're saying that we need at least 1 letter [a-zA-Z]+ followed by zero or many spaces \s* and we repeat the whole thing one or many times ([a-zA-Z]+\s*)+
The above will work if you don't want the name to start with spaces otherwise you can use:
(\s*[a-zA-Z]+\s*)+
That's the same pattern but with zero or many leading spaces \s*
I think this works for you.
It is only accept letter and spaces.
^[a-zA-Z\s]*$
What is the correct pattern for a text input to only allow uppercase letters, lowercase letters, and commas?
I know that this is correct for the letters:
pattern="[a-zA-Z]"
but I dont know how to allow commas.
Thanks for any help!
Short answer:
pattern="^[a-zA-Z,]*$"
A couple of comment:
* means zero or more characters which means this patter will allow empty fields as well. If you want to guarantee that it will contain at least one character, use + instead of *.
^ means beginning of the string and $ is the end. If you don't use them then something like this would be possible "!#123asdSDADS,,,21312312(2"
I have a regex '^[A0-Z9]+$' that works until it reaches strings with 'special' characters like a period or dash.
List:
UPPER
lower
UPPER lower
lower UPPER
TEST
test
UPPER2.2-1
UPPER2
Gives:
UPPER
TEST
UPPER2
How do I get the regex to ignore non-alphanumeric characters also so it includes UPPER2.2-1 also?
I have a link here to show it 'real-time': http://www.rubular.com/r/ev23M7G1O3
This is for MySQL REGEX
EDIT: I didn't specify I wanted all non-alphanumeric characters (including spaces), but with the help of others here it led me to this: '^[A-Z-0-9[:punct:][:space:]]+$' is there anything wrong with this?
Try
'^[A-Z0-9.-]+$'
You just need to add the special characters to the group, optionally escaping them.
Additionally if you choose not to escape the -, be aware that it should be placed at the start or the end of the grouping expression to avoid the chance that it may be interpreted as delimiting a range.
To your updated question, if you want all non-whitespace, try using a group such as:
^[^ ]+$
which will match everything except for a space.
If instead what you wanted is all non-whitespace and non-lowercase, you likely will want to use:
^[^ a-z]+$
The 'trick' used here is adding a caret symbol after the opening [ in the group expression. This indicates that we want the negation of the match.
Following the pattern, we can also apply this 'trick' to get everything but lowercase letters like this:
^[^a-z]+$
I'm not really sure which of the 3 above you want, but if nothing else, this ought to serve as a good example of what you can do with character classes.
I believe you are looking for (one?) uppercase-word match, where word is pretty much anything.
^[^a-z\s]+$
...or if you want to allow more words with spaces, then probably just
^[^a-z]+$
You just need to put in the . and -. In theory, you don't need to escape because they are inside the brackets, but I like to to remind myself to escape when I have to.
'^[A-Z0-9\.\-]+$'
Try regular expression as below:
'^[A0-Z0\\.\\-]+$'